It's not so clear to me if useTransition, useOptimistic are part of the problem or part of the solution. (e.g. "looking responsive" could be the enemy of "being responsive", right now I am fixing a ticket about an incorrect state that flashes for < 0.5 sec that drives some people crazy, if I wanted something different in my framework it would be "update the UI state once, it renders once and doesn't keep calling effects and setters for an indefinite time")
Funny I am advocating for a React 19 update because at least React 19 can tell the test framework when it is done running callbacks, it might have me writing tests for components again.
[1] ... and if I want to SSR I might just ditch React and build the kind of apps that I built in 1999 with maybe a little help from HTMX
edit: it's also a great source of laughs if you enjoy AI hallucinations. eg. ask it to generate a use action state solution which updates a select element.